Variable throat nozzle



y 6, 1955 w. B. WILSON, JR 3,192,710

VARIABLE THROAT NOZZLE Filed Oct. 17, 1962 4 Sheets-Sheet l FIG. 1

Walter B. Wilson, Jr.,

INVENTOR.

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y 6, 1955 w. B. WILSON, JR 3,192,710

VARIABLE THROAT NOZZLE Filed 00" 17, 1962 4 Sheets-Sheet 2 Walter B. Wilson, Jr. INVENTOR.

July 6, 1965 w. B. WILSON, JR

VARIABLE THROAT NOZZLE 4 Sheets-Sheet 5 Filed Oct. 17, 1962 9 M21 W ZW W w.

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Walter B. Wilson,Jr., mmvrozz.

United States Patent 1 3,192,710 VARIABLE THROAT NOZZLE Walter B. .Wilson, Jr., Huntsville, Ala., assignor to the United'States of America as represented by the Secretary of the Army Filed Oct. 17, 1962, Ser. No. 231,303

3 Claims. (CI. 6035.6) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

This invention pertains to a variable throat nozzle. More particularly the invention relates to a nozzle for use with a rocket or other jet type motor wherein the size of the unobstructed throat area of the nozzle may be changed while the missile on which the motor is mounted is in flight.

In the use of missiles and other jet driven devices, and particularly those employing solid fuels, it is advantageous to be able to vary the size of the throat orifice of the emission nozzle to regulate the amount of thrust developed by the motor.

An object of the present invention is to provide a nozzle having means to vary the unobstructed area at its throat zone.

Another object of the invention is to provide a nozzle wherein the unobstructed cross sectional area of the throat zone may be changed to vary the thrust developed by the discharge of gas through the nozzle.

A further object of the invention is to provide a nozzle wherein the previous objects can be accomplished during flight of the missile or other device upon which the nozzle is mounted.

An important feature of the invention is the provision of a nozzle wherein cam means are employed to shift the nozzle venturi axially with respect to a fixed conical probe projecting therethrough to thereby change the size of the unobstructed area of the throat orifice.

These and other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a sectional view through a nozzle employing the principles of the present invention;

FIGURE 2 is a section taken on line 2-2 of FIG- URE 1;

FIGURE 3 is a partial section taken generally on line 3-3 of FIGURE 1; and

FIGURE 4 is a section taken on line 4-4 of FIG- URE 1.

Referring now to the drawings and particularly to FIGURE 1 thereof, the nozzle assembly of the present invention comprises an adaptor fitting 16 at its forward end which fitting is screwed into the rear of the propellant chamber 14 as indicated at 12. A main support sleeve 18 is connected to adaptor fitting 16 by threads 20 and projects rearwardly from said adaptor fitting. A spider 22 is screwed into the forward end of support sleeve 18. Spider 22 is provided with a plurality of axially extending passageways 24 to permit the passage of gases therethrough. A conical shaped probe 26 is supported at its base by spider 22 and projects rearwardly therefrom. Probe 26 is in two parts, namely, a support rod 28 screwed into spider 22 at 30 and a conical outer member 32 of heat resistant or refractory material.

A nozzle sleeve assembly 40 is mounted within support sleeve 18 for axial sliding movement with respect thereto. The nozzle sleeve assembly comprises and outer metal sleeve 42, an inner liner 44 of heat resistant reice fractory material and having a venturi shaped passageway 46 therethrough, and a cap member 48. A slide block 50 is connected to nozzle assembly 40 by cap screws 52 and projects radially therefrom through an axially extending slot 54 formed in support sleeve 18. An O-ring 56 mounted in a groove 58 in the inner wall of support sleeve 18 seals against the outer wall of outer sleeve 42 of nozzle assembly 40.

- A third sleeve 60 is rotatably mounted on main support sleeve 18 by bearings 62 and 64, and a thrust bearing 66 is interposed between the rear end of cam sleeve 60 and a cap member 68 secured to the rear end of support sleeve 18 by a plurality of cap screws 70. A roller 72 is mounted on slide block 50 by means of a pin 74 and projects radially into a helical cam slot 76 formed in the third or cam sleeve 60.

A ring gear 80 is formed on the outer surface of cam sleeve ,60 and meshes with two spur gears 82 and 84 mounted on the shafts of two reversible servomotors 86 and 88, respectively. Servomotors 86 and 88 are mounted on brackets 90 and 92 fixed to main support sleeve 18 at diametrically opposed positions. An outer sleeve 94 is bolted to the peripheral surfaces of adaptor fitting 16 and cap 68 by cap screws 96 to enclose and protect the several moving parts.

In the operation of the device to change the thrust output of the rocket motor, of which nozzle 10 of the present invention is a part, servomotors 86 and 88 are energized for rotation in one direction or the other to rotate cam sleeve 60. Rotation of cam sleeve 60 effects longitudinal axial movement of slide 50 and nozzle assembly 40 through the cam slot 76 and roller 72 thus moving the throat area of v'enturi passage 46 toward or away from the large end of cone shaped probe 26. The movement of venturi passage 46 relative to probe 26 changes the unobstructed area of the throat to thereby regulate the amount of thrust developed by the nozzle.

While a preferred embodiment of the invention has been shown and described herein, it is evident that changes may be made in said embodiment without departing from the spirit of the invention as defined in the appended claims.

The invention having thus been described, what is claimed as new and desired to be protected by Letters Patent is:

1. A nozzle assembly for a rocket motor comprising: a main support sleeve fixed to said motor and projecting rearwardly therefrom, a nozzle sleeve slideably mounted within said support sleeve for longitudinal movement only with respect to said support sleeve, said nozzle sleeve having a venturi shaped inner surface, a conical probe fixed to said motor and projecting rearwardly therefrom through said nozzle sleeve, a third sleeve mounted on said support sleeve for rotation with respect thereto, and means interconnecting said third sleeve and said nozzle sleeve whereby rotation of said third sleeve imparts longitudinal movement to said nozzle sleeve relative to said probe, and means for imparting rotation to said third sleeve before and during the firing of said rocket motor.

2. A nozzle assembly for a rocket motor comprising: a main support sleeve having a longitudinally extending slot formed therein fixed to said motor and projecting rearwardly therefrom, a nozzle sleeve slideably mounted within said main support sleeve, the inner wall of said nozzle sleeve being venturi shaped, a sliding block fixed to said nozzle sleeve and projecting radially through the slot in said main support sleeve, a conical probe fixed to said motor and projecting rearwardly therefrom through said nozzle sleeve, a cam sleeve having a helical cam slot formed therein, mounted for rotation only on the outer surface of said main support sleeve, a cam pin fixed to said sliding block and projecting radially through said helical slot in said cam sleeve for movement therein responsive to rotation'of said cam sleeve, and means for rotating said cam sleeve relative to-said main support sleeve for movement of said cam pin in said slot to impart longitudinal movement of said nozzle sleeve Within said support sleeve relative to said probe while the rocket motor is firing.

3. A nozzle assembly as set forth in claim 2, wherein the means for rotating said cam sleeve comprises a ring gear fixed to said cam sleeve, a reversible servomotor fixed to said main support sleeve, and a spur gear on.

said servomotor meshing with the ring gear on said cam sleeve.

References Cited by the Examiner UNITED STATES PATENTS SAMUEL LEVINE, Primary Examiner. ABRAM BLUM, Examiner. 

1. A NOZZLE ASSEMBLY FOR A ROCKET MOTOR COMPRISING: A MAIN SUPPORT SLEEVE FIXED TO SAID MOTOR AND PROJECTING REARWARDLY THEREFROM, A NOZZLE SLEEVE SLIDEABLY MOUNTED WITHIN SAID SUPPORT SLEEVE FOR LONGITUDINAL MOVEMENT ONLY WITH RESPECT TO SAID SUPPORT SLEEVE, SAID NOZZLE SLEEVE HAVING A VENTURI SHAPED INNER SURFACE, A CONICAL PROBE FIXED TO SAID MOTOR AND PROJECTING REARWARDLY THEREFROM THROUGH SAID NOZZLE SLEEVE, A THIRD SLEEVE 